Llullaillaco National Park covers 268,670 hectares and lies 275 km southeast of Antofagasta close to the border with Argentina. Its centrepiece is the 6739m / 22,110ft high Llullaillaco volcano, the 7th highest mountain in South America and the 2nd highest active volcano in the world (after Ojos del Salado). In 1999 a team of archeologists led by Johan Reinhard found three mummies of children (probably sacrifices) dating from the Inca period close to the summit. Llullaillaco appears to have been the most important sacred mountain for the Incas in the region, there are Inca roads in the Park and several other archeological sites on the flanks of the volcano. The Park is in the high altitude Puna de Atacama region above the Atacama Desert, and also contains the Punta Negra, Pajonales and Aguas Calientes IV salt flats / lakes.